An Argentinian M38 ‘Casco’ Stahlhelm.
During the late 30s, Argentina was buying equipment from Germany, and during that time around 300 German helmets came into their country.
Argentina later began to make their own helmets known as the ‘Casco’ which was patterned after the various German helmets. The example above is a native made version, which has a small National roundel.
During the 70s a large amount of these were being sold as original German WWII Stahlhelms in various Guns and WWII History magazines.
Three major clues that can help identify this as not being German manufactured are: the rivets are larger than the German versions, and the shape of the helmet from the side (German helmets tend to have a more dramatic ‘slope’ from the rear). But the major clue: Germans stamped their helmets and these markings were always placed in one of two places; the center of the left underside rim or the center rear of the skirt.